无结构土壤透气性的初步研究

土壤的透气性是指土壤让空气穿透本身的能力。透气性是土壤很重要的物理性质,因为它不仅决定了土壤与大气间空气交换的速度^[1],而且和土壤的持水性有关^[2],测定土壤的透气性还可以了解土壤其他一系列的物理性质如排水的能力^[3]、地表迳流的速度^[2]、耐蚀性、空气容量^[3]及其结构性的程度等等。土壤中微生物活动的方向与强度、种籽的发芽、根系的发育及其吸收能力、土壤中养分的状态^[4]和影响农作物生活的其他重要土壤因素都有赖于土壤的透气性。     

磷肥在土壤中的转化及其与土壤有效磷的关系

自从张守敬和Jeckson(1957年)提出土壤无机磷分级方法以来,国内外许多土壤农业化学家对土壤有效磷与各级无机磷之间的关系^[1],作物吸磷状况与土壤无机磷组成的相关性^[2],水稻生长期间土壤有效磷增加的机理^[3],以及磷肥对土壤无机磷组成的影响和转化等方面作了广泛的研究^[4]。     

旱地加水可促进微生物对γ-666的降解

γ-666在含水率低的旱地土壤中持留期可长达3—11年之久,并可引起水质、土壤和植物的污染^[1]。从60年代以来,许多学者对渍水土壤中微生物对γ-666的降解作用已作了大量研究^[1-7]。确定渍水土壤中γ-666的降解比旱地土壤容易得多^[1-3],并先后分离到了二株嫌气性降解菌^[2,4,7]。     

油-稻轮作条件下土壤硫形态消长规律的研究

土壤无机硫主要是水溶和吸附态SO₄^2-,它能被作物直接吸收。有机硫是作物利用硫的主要来源,分为HI还原有机硫(硫酸酯)、碳键硫(C-S)和惰性硫。有机硫只有转化为SO₄^2-后才能为作物吸收^[1]。土壤硫形态转化规律室内培养和盆栽研究较多^[1,2],田间试验研究较少,国外探讨了油菜一休闲制中土壤硫形态转化规律^[3]。水一早轮作制是中国主要轮作制之一,该轮作制中土壤处于干一湿交替之中,土壤硫转化规律可能有其特异性。本研究选择油一稻轮作制为研究对象,研究土壤硫形态消长和分配规律。其结果将为评价土壤供硫能力和了解土壤硫肥力维持机制提供依据。     

天津地区土壤中若干金属元素间的相关性

土壤中的元素主要来源于成土母质^[1],但在风化成土过程中,元素的迁移与富集能力各不相同。为了寻求土壤中元素间的内在联系,判断元素的含量和分布状况,元素间的相关分析法是良好的方法之一。例如,Ure等^[6]测定了苏格兰不同母质的土壤中多种微量元素含量,并讨论了各元素间的相互关系。Pilotte等^[5]用相关性分析法对河口地区沉积物中元素含量进行判断,浅见辉男等^[4]用元素相关性描述了沉积物中元素分布,梁伟^[5]用元素相关性对土壤背景值进行判断等。本文根据天津地区土壤表土中16个元素之间的相关系数,探讨元素的地球化学性质对元素间的相关性的影响。     

土壤吸收量是土壤肥沃度的一项重要指标

土壤吸收性能的研究,自上世纪Way,Bemmelen 以来,吸引过很多土壤化学家的注意,诸如К.К.Гедройц^[1],А.Н.Соколовский^[9].Н/П/Ремезов^[8],Н.И.Горбунов^[3]等。     

塿土剖面CO2浓度的动态变化及其受环境因素的影响

CO₂是土壤空气的重要组成,土壤空气CO₂浓度一般高于大气几倍到数十倍,甚至上百倍^[1]。土壤空气中CO₂主要来源于土壤呼吸,其浓度主要决定于生物因素(植物根系、土壤微生物活性等)和环境因素(土壤温度、含水量等)^[2～4]。土壤空气CO₂浓度可以反映和影响土壤向大气释放CO₂的通量^[4,5],同时对植物根系生长发育、土壤微生物活动和各种养料物质转化也有很大影响^[1]。研究了解土壤空气CO₂浓度剖面分布、季节动态及其影响因素,有助于人们认识土壤中CO₂产生、累积、输运以及向大气排放的生物和物理过程,制定和实施合理的农作措施以改善作物生长环境和减少土壤向大气排放的CO₂。国外已在森林、草地和农田土壤上开展了较长时间的土壤空气CO₂浓度观测研究^[4~7],但我国的研究和报道很少^[8,9]。本文通过土壤剖面不同深度CO₂浓度的定位观测,初步揭示了土剖面CO₂浓度的分布特征、季节动态及其受水热条件的影响。     

华北平原瓦碱的特性和形成

华北平原广泛分布着一种具有灰白色紧实结壳的土壤,群众称为瓦碱(或岗瓦碱)。这种土壤在冀^[1]、鲁^[2]、豫^[3]、苏^[4,5]、皖^[6,7,8]五省都有分布,一般认为这是一种碱化土壤,但其性质及形成过程还不够清楚。根据国内外的研究资料,碱化土壤多分布于栗钙土、黑土及棕色荒漠草原土带,至于褐土带地区浅色草甸土发生碱化过程,在土壤学研究中还是一个新问题。因此,我们曾对山东、河南某些瓦碱进行了一些工作,今将初步结果报导如下。     

土壤湿度计的原理与应用

土壤湿度计,又名张力计^[4]、负压计^[1],是测量土壤吸(水)力的一种仪器。     

土壤空气研究概况

土壤空气是土壤物理学研究领域内比较薄弱的一个分支学科^[3].但是,它在土壤形成过程中和土壤肥力的培育过程中却占有十分重要的地位.Вернаднский^[7]曾以“无气体不成土壤”这句话来表达土壤空气与土壤之间的相互关系.     

铁氧化物与土壤表面电荷性质的关系

The relationship between iron oxides and surface charge characteristics in variable charge soils (latosol and red earth) was studied in following three ways.(1)Remove free iron oxides (Fed) and amorphous iron oxides (Feo) from the soils with sodium dithionite and acid ammonium oxalate solution respectively.(2) Add 2% glucose (on the basis of air-dry soil weight) to soils and incubate under submerged condition to activate iron oxides,and then the mixtures are dehydrated and air-dried to age iron oxides.(3) Precipitate various crystalline forms of iron oxides onto kaolinite.The results showed that free iron oxides (Fed) were the chief carrier of variable positive charges.Of which crystalline iron oxides (Fed-Feo) presented mainly as discrete particles in the soils and could only play a role of the carrier of positive charges,and did little influence on negative charges.Whereas the amorphous iron oxides (Feo),which presented mainly fas a coating with a large specific surface area,not only had positive charges,but also blocked the negative charge sites in soils.Submerged incubation activated iron oxides in the soils,and increased the amount of amorphous iron oxides and the degree of activation of iron oxide,which resulted in the increase of positive and negative charges of soils.Dehydration and air-dry aged iron oxides in soils and decreased the amount of amorphous iron oxides and the degree of activation of iron oxide,and also led to the decrease of positive and negative charges.Both the submerged incubation and the dehydration and air-dry had no significant influence on net charges.Precipitation of iron oxides onto kaolinite markedly increased positive charges and decreased negative charges.Amorphous iron oxide having a larger surface area contributed more positive charge sites and blocked more negative charge sites in kaolinite than crystalline goethite.     

苏南水稻土对铜离子专性吸附的初步研究

六十年代以来,土壤对多价离子特别是重金属离子的专性吸附,已日益成为土壤化学领域中一个受人注意的问题。土壤胶体中铁、锰、铝、硅等氧化物及其水合物和土壤有机质是专性吸附的主要载体^{[12,16,17,19,20,21]},它们对许多重金属元素的专性吸附所引起的富集过程,起着控制这些金属元素在土壤溶液和海水中浓度的作用^[9,15,18];一些微盒营养元素在土壤中的移动及其对植物的有效性,也深受土壤中氧化物胶体的专性吸附的影响^[11,14,21]。因此,铁、锰等水合氧化物对重金属离子的专性吸附的研究,不仅是土壤化学领域,而且也是土壤环境保护和地球化学等领域中的重要研究课题。     

Contribution of Iron and Aluminum Oxides to Electrokinetic Characteristics of Variable Charge Soils in Relation to Surface Charge

The contribution of iron and aluminum oxides to electrokinetic characteristics of variable charge soils was studied through determination of electrophoretic mobilities of the red soils treated with either removal of iron oxides or coating of aluminum oxides,and of those deferrated under natural conditions.After removal of the iron oxides,zeta potentials of the latosol and the red earth decreased obviously with a shift of IEP to a lower pH,from 6.4 to 5.3 and 4.1 to 2.4 for the former and the latter,respectively,and the electrokinetic change for the latosol was greater than for the red earth.Zeta potentials of the kaolinite sample increased markedly after coated with iron oxides.The striking effect of iron oxides on electrokinetix properties of the soils was also demonstrated by the electrokinetic differences between the samples from the red and white zones of a plinthitic horizon formed naturally,and between the samples from the gley and bottom horizons of a paddy soil derived from a red earth.The coatings of aluminum oxides on the latosol and the yellow earth made their zeta potentials rise pronouncedly and their IEFs move toward higher pHs,from 6.2 to 6.8 and 4.3 to 5.3 for the former and the latter,respectively.The samples with different particle sizes also exhibited some electrokinetic variation.The experiment showed that the effects of iron and aluminum oxides were closely related to the pH and type of the soils.     

粘粒矿物和有机质对土壤胶体比表面的影响

分别从黑土、黄绵土、黄棕壤、红壤和砖红壤提取<2nm的胶体,测定去有机质前后土壤胶体比表面;并用猪粪中提取的胡敏酸与上述5种土壤胶体相作用,由泥炭中提取的胡敏酸与蒙脱石、伊利石、高岭石相作用,测定其复合胶体的比表面;研究了粘粒矿物类型和胡敏酸对土壤胶体比表面的影响。结果表明,土壤胶体比表面大小与其所含主要粘粒矿物类型密切相关。5种土壤胶体比表面大小为:黑土>黄棕壤>黄绵土>红壤>砖红壤。砖红壤胶体去游离氧化铁后,胶体比表面明显降低;但黄棕壤胶体去游离氧化铁后比表面反而增加。有机质对土壤胶体比表面的影响因土壤类型不同而异,去除有机质后,黑土、黄绵土和黄棕壤胶体的比表面增加;而红壤、砖红壤胶体的比表面无明显变化。黑土和黄棕壤胶体与猪粪胡敏酸复合后,比表面降低;而砖红壤胶体与猪粪胡敏酸复合后反而增加。泥炭胡敏酸与蒙脱石、伊利石胶体复合后比表面降低;而高岭石却增加。     

对黄壤发生分类的看法

长期以来我们对黄壤的发生、特性和分布总觉得模糊不清。在土壤调查制图时;因红壤黄壤在形态性质上不易区分,所以在确定南方山地红壤带和黄壤带的垂直分布界线时,只有按海拔高度来划分。1982年10月在重庆召开的第三次全国森林土壤学术讨论会上有两篇都是有关广东鼎湖山的土壤论文,其中一篇把红壤黄壤界线划在300米,而另一篇划在700米,说明划分标准还不统一。云贵高原是我国黄壤集中分布区,根据已有的资料看来,那里的黄壤是否典型、黄壤是否为湿润气候的产物,都值得讨论。本文就多年来的考察,结合有关论著,谈一点不成熟的看法,希望能起到抛砖引玉的作用。     

淹水还原作用对红壤镉生物有效性的影响

用添加20 mg.kg^-1镉（Cd）的红壤（pH 4.46）室温淹水培养41 d,研究淹水还原作用对Cd溶解性的影响,同时设置水稻培养试验,在红壤淹水初期（1-11 d）和后期（淹水31-41 d）植入水稻秧苗,以比较不同淹水时段红壤Cd对水稻的有效性。结果表明,红壤淹水后1-25 d水溶性Cd浓度由0.210 mg.L^-1上升到0.254 mg.L^-1,淹水28-40 d水溶性Cd浓度由0.221 mg.L^-1下降到0.092mg.L^-1,在淹水1-11 d和31-41 d水稻茎叶Cd含量分别为48.37和16.25 mg.kg^-1。说明淹水初期红壤Cd活性和生物有效性高于淹水后期。通过红壤淹水过程Fe、Cd溶解性及CEC、阳离子饱和度等的研究,表明红壤淹水后氧化铁的还原溶解作用导致pe＋pH下降和pH上升,由此控制着Cd活性和生物有效性的升降。     

Redistribution of copper in alfisols under submergence. I. native copper

Abstract

Rice farmers apply organic matter and phosphatic fertilizer before or at the time of puddling (an operation involving tilling of puddled soil before transplanting of rice seedlings) as a part of their soil management program for growing wet land rice. This brings about changes in chemical environment which modifies micronutrient redistribution among soil fractions and thus, their availability to rice crops. An experiment was conducted to understand the effect of organic matter and phosphorus (P) on transformation of copper (Cu) in Alfisols under submergence. Soils were incubated for 75 days in the laboratory under submerged condition and were analyzed for different fractions of Cu content at periodic intervals. Copper was mobilized from water soluble plus exchangeable (WSEX), organically complexed (OC), and crystalline iron (Fe) oxides (CRYOX) bound fractions to amorphous iron oxides (AMOX) and residual (RESID) fractions, the rate of mobilization being maximum from CRYOX and to RESID fraction during initial 15‐day period. Organic matter application retarded Cu transformation from OC and into RESID fraction and increased its content in AMOX fractions. It also decreased WSEX Cu markedly. Copper transformation was not significantly influenced by P application.     

Influence of organic matter on phosphate adsorption by aluminium and iron oxides in sandy soils

The phosphate adsorption capacity (P_max) of samples from various horizons of five Danish podzolized soils were investigated before and after organic matter removal. Removal of organic matter had no direct influence on P_max suggesting that organic matter did not compete with phosphate for adsorption sites. In the soils investigated aluminium and iron oxides were the main phosphate adsorbents. Thus, more than 96% of the variation in P_max could be accounted for by poorly crystalline aluminium and iron oxides (extractable by oxalate) and by well-crystallized iron oxides (taken as the difference between dithionite-citrate-bicarbonate-extractable iron and oxalate-extractable iron). Organic matter affected phosphate adsorption indirectly by inhibiting aluminium oxide crystallization. The resulting poorly crystalline oxides had high P_max. In contrast, the influence of organic matter on the crystallinity of the iron oxides, and therefore on their capacity to adsorb phosphate, seemed limited.     

Influence of soil moisture on sulphur oxidation in brown earth soils exposed to atmospheric pollution

Summary Laboratory studies were conducted to determine the influence of soil moisture on S oxidation in atmospheric-polluted brown earth soils. Elemental S was oxidized to sulphate over a wide range of soil moisture treatments (10%–60% w/w), but occurred optimally at around 40%–50% soil moisture content (0.08 MPa). Thiosulphate and tetrathionate were found only in soils incubated at low moisture contents. S-oxidation generally acidified the soils, but an increase in soil pH occurred at high moisture levels, where soils were waterlogged. The S oxidative ability of soil samples collected at monthly intervals and incubated with elemental S in the field-moist state was also strongly influenced by soil moisture content. The rate of sulphate production was greatest in the brown earth soil exposed to heavy atmospheric pollution from a coking works.     

Redistribution of copper in alfisols under submergence. II. applied copper

Abstract

Soil submergence for growing wet land rice creates typical chemical environment which is likely to affect availability of applied fertilizer copper (Cu) to the crop by transforming it into various soil fractions. An experiment was undertaken to study the effect of organic matter (as starch) application on the transformation of applied Cu in Alfisols under submergence. Copper was applied either at the beginning or after 15 days of submergence (presubmergence). Results show that more than 85% of the applied Cu was distributed in water soluble plus exchangeable (WSEX), organically complexed (OC), and amorphous iron oxides bound (AMOX) fractions at the beginning of incubation. Submergence caused decrease in WSEX, and OC [in Purulia district (S,) soil only] fractions and increase in AMOX and residual Cu fractions of applied Cu. About 15% of the applied Cu was transformed into inactive residual fraction at the end of 60 days of submergence. Copper applied in 15 days presubmerged soils transformed to a lesser extent into residual fraction than that applied in 0 day presubmerged (i.e., no presubmergence) soils. Application of organic matter in S, soil mobilized applied Cu from OC to AMOX fraction and reduced net transformation into residual fraction. Lower net transformation into residual fraction suggests that Cu may be applied in 15 days presubmerged soil for its higher use efficiency in rice crop grown in Cu deficient Alfisol.